Oil burner muffler



April 11, 1939. J. H. MclLvAlNE 2,154,133

' OIL BURNER MUFFLER 3 Filed April 3, 1937 Planted Apr. 11, 1939 on. BURNER MUFFLER John H. McIlvaine, Chicago, 1li., assigner to I Mcllvainc Burner Corporation, Chicago, Ill., a corporation of Illinois Application April 3, 1937, Serial No. 134,699

` 15 Claims.

I'his invention relates to oil burners for domestic heating furnaces.

During the past few years there has been considerable thought given to obtaining quiet op- 5 eration of oil burners but, so far as I am aware, it was not heretofore fully realized to what an appreciable degree noisy operation was traceable to the air tube telephoning the combustion noises from the furnace. As a result, most of 1I) the improvements made with a special view to quietness of operation have been confined to other portions of the apparatus.v When transverse bellies were provided of suillcient size to cut down the transmission of sound, they invariably inter- 13 fered with the free ilow/ of air, and hence such constructions have not been practical. Special formations of air tubes have been tried with a view to overcoming that diillculty, but 'invariably they have not provided the desired silent opera- 20 tion. It is the principal object of my invention to provide an oil burner, the air tube of which incorporates a kmuilier so constructed that while it does not interfere in any way with the delivery of air from the blower to the combustion Il head or ilrepot, the transmission of sound from within the furnace is efl'ectually cut on by entrapment and absorption in the muiiier with the result that the burner operates much more quietly than heretofore.

.0 The invention embraces other objects and advantages hereinafter pointed out in the description of the accompanying drawing, in which- Figure 1 is a view partly in longitudinal vertical section and partly in side elevation of an 3l oil burner installation illustrating the mumer chambe of my invention;

Pig. 2 is a horizontal section on the line 2-2 of Figure 1 on`an enlarged scale;

Fig. 3 is a cross-section in a vertical plane on theline3-'3ofFigureLand .K

Fig. 4 is a sectional detail in a vertical plane on the line #-4 of Fig. 3.

The same reference numerals are applied to corresponding parts throughout the views.

4l The oil burner shown in Figure 1 is generally similar to that disclosed in the ,copending application of Peter I. Hollman and myself, Serial No. 74,952. filed April 17, 1936. 'I'he combustion head or ilrepot 5 disposed inside the furnace 6 forms I the subject matter of another joint application of Peter I. Hollman and myself, Serial No. 165,262 filed September 23, 1937, and comprises, generally speaking, a metal overflow pan 1 cast integral with the end of the air tube or conduit 3, u a metal tray 3 placed in the pan 1, and a ceramic ring I0 resting on the pan and surroundingthe tray, formed with a top II provided with an oblong or oval-shaped central flame opening I2. The air tube 8 is supported inside the furnace by the hollow boss I3 cast integral with the pan 1 5 and having the vertical supporting post Il extending therethrough, as shown. vwith adjusting and locking nuts I and I6 threading thereon and engaging the bottom and top of the boss I3. The blower housing ,I1 has a web I3 cast integral 10 therewith and terminating in a trip bucket housing I3 that is supported on opposite sides by feet bolted adjustably thereto, as at 2|. The blower housing has a tangential discharge neck 22 which is anged, as at 23, for fastening the u same to the outer end of the air tube 3, as by means of bolts 24. A gasket 2 5 of compressible material is interposed at the connection to prevent air seepage. The blower housing has an alrimpeller therein driven preferably at a constant I speed by means of an electric motor seated on the opposite side of the housing from the shutter plate 26. I'he latter has openings 21 which register with openings in the side wall of the housing I1 in diierent positions of rotation of the plate l about its center 23. The shutter mechanism is covered in my Patent 1,797,293 wherein I Ihave described how the closure plates 2l are adjusted relative to the openings 21 so that only the proper amount of air will be allowed to enter the blower housing I1 at each one of a series of positions of the shutter plate, the shutter plate at the time 'of installation of the burner being turned one step at a time and the appropriate closure plate being adjusted at each step so as to secure the 3l correct amount of air in proportion to oil. A link 30 provides an operating connection between the, shutter plate 2B and the rotatable crank arm 3l of the regulator 32,.. that is, where automatic control is desired. In some installations a remote H control unit is provided having connection with the shutter plate 26 for direct manual adjustment thereof. In the automatic control the room thermostat located conveniently upstairs causes the regulator 32 to operate so as to regulatey the 4l size of the ame and always balance the heat los of the building and accordingly maintain an even temperature. Another link 33 provides an 0perating connection between the shutter plate 23 and a lever 34 adjustably connectedwith a le quadrant 35 fixed to the rotatable stem of the control valve 36 so that the control valve will beopened wider and wider at each step in the progressive opening of the shutter plate, whereby to secure correct proportioning of oil and air for Il each flame, from the low flame that serves as a pilot through the various intermediate sized ames up to the high flame.

'Ihe oil, the iiow of which is controlled by the valve 36, is delivered through the pipe 31 by gravity feed to a filter 38 communicating directly with a float valve, the purpose of which is to maintain a constant level of fuel in relation to the tray 9 in the combustion head. The oil flows from the float valve by gravity feed to a solenoid valve 39, the function of which is to permit an unrestricted flow therethrough so long as the cunent for the motor of the blower is not interrupted. If the current is interrupted, the solenoid valve automatically operates to reduce the flow of oil to about one-third the maximum capacity of the burner, sufficient for it to continue operating on natural draft and suillcient to keep the house warm until normal operation is resumed. The oil passes from the solenoid valve into the control valve and flows from this valve by gravity feed through the pipe connection 40 to the pipe 4I which extends lengthwise inside the air tube 8 and has an upwardly and downwardly bent end 42 to discharge the oil into the groove 43 in the tray 9. The oil so discharged is vaporized and mixed with air from the tube l and burned in the combustion head 5 in the manner substantially as set forth in the first mentioned copending application.

In accordance with my invention, the air tube 8, instead of having the same sized bore from the point of its connection with the neck 22 to the point of its communication with the combustion head 5, as indicated at 44, is of increased width and height from its outer end all the way in nearly to the point of connection with the combustion head to provide a mufller indicated generally by the reference numeral 45. Reinforcing ribs 46 are cast integral with the bottom of the tube 8 between the end wall of the muiller chamber 41 and the adjoining side of the overflow pan 1. In other words, the muffler forms a portion of the length of the air tube and, as will soon appear, is so constructed that while it a1- lows free passage of air from the blower housing I1 to the combustion head 5, it effectually cuts oi the transmission of sound from the furnace by entrapment and absorption within the mumer chamber 41.A To begin with, it is apparent from Figs. 2 and 3 that the verticalrwalls or bailles 4l projecting inwardly from the opposite sides of the chamber 41 in staggered relation and around which the sound deadening felt 49 is wound or threaded, are amply spaced laterally with respect to one another for free passage of air through the muiller chamber from the discharge neck 22 of the blower housing I1 to the combustion head 5. The fuel feed pipe 4i also extends lengthwise through the chamber 41 between these baiiles, as indicatedin Figure 1. However, owing partly to the fact that the outer ends of the walls 48 are enlarged, as at 48', so that the intervening stall-like spaces 51 are narrower at their entrances than attheir inner ends to serve as sound traps, and partly to the fact that there is moreover good absorption and `deadening of sound throughout the interior of the muffler by reason of the lining of the end and side walls with the felt 49 and the lining of the top and bottom walls with felt, as indicated at 50 and 5|, sound cannot travel back from inside the furnace 5 through the muiiler chamber 41, The felt, in other words, prevents the transmission of sound by reflection off the walls of the air tube, and the bottle-neck restriction of the outer ends of the stalls 51 interferes with escape of sound therefrom. Then, too, there is good assurance that the sound will be thrown into the stalls 51 by causing the air to flow along a zigzag or sinuous path by reason of the staggered relationship of the walls 48 on one side of the muffler in relation to the walls 45 on the other side. I have found that with my construction, at least 90% of the combustion noise otherwise audible outside the furnace 5 is not apparent. I'his naturally is a great advantage in the home. The addition of the muiller chamber is considered preferable, for example, to the redesigning of the combustion head to a form operating more quietly but less eiiiciently. VThis is mentioned because efforts to obtain quiet operation by redesign of the combustion head or firepot usually necessitate a compromise and lower eiliciency is tolerated in return for quieter operation. With the present invention there is no such compromise necessary.

Figs. 3 and 4 show that the baiiles 48 projecting from the side walls of thechamber 41 terminate in spaced relation to the top and bottom walls 52 and 55. In that way the felt 59 extending the full width of the chamber 41 can be placed between the ends of the bailles 48 and the top wall 52 either before or after the felt 49 covering the side walls and baffles is placed, and the felt 5I will be supported by the bailles 48 and felt 45 to a certain extent, although I prefer to cement the felt 50 in place. The felt 49 is held in place by wires 54 which are bent to U-shape so as to extend over the tops of the bailles and along the felt on opposite sides, as clearly appears in Figs. 2 and 4, the ends of the wires being bent inopposite directions under the lower ends of the bailies and against the felt on the opposite sides, as indicated at 55 in Figs. 3 and 4. The enlarged outer ends 45 of the baille walls 4l are formed preferably to a cloverleaf cross-section, as lndicated, so that there are sharply defined shoulders behind the enlarged ends and the wire fasteners 54 arel not apt to slip off in the placing of the felt on the bafile walls. 'I'he bottom wall 52 is a separate cover plate suitably secured in place by screws 56 and the felt y5I is cemented thereto and extends beneath the baiiies 45, as clearly appears in Fig. 3.

It is believed the foregoing description conveys a good understanding of my invention. 'I'he appended claims have been drawn with a view to covering all legitimate modifications and adaptations.

I claim:

l. A noise muiller for an air delivery'conduit for an oil burner in a furnace adapted to be supplied with air under pressure from a blower, said muiiler comprising an elongated casing, opposed longitudinal walls of which are formed to provide stalls opening oi a longitudinal air passage through said casing, the walls of said stalls being covered with sound absorbing material, each of the stall spaces defined by said sound absorbing being covered with sound absorbing material. each ofthestallspaoesdeiinedbysaidsound absorbing material being of dovetail cross-section narrow at the entrances and wide remote from said entrances. substantially as and for the purpose described. the stalls on one wall being in staggerec relation to the stalls on the opposite wall of said casing.

3. A noise muiling air delivery tube for an oil burner in a furnace including an elongated mufiier casing having an inlet at` one end remote from the burner and an outlet at the other end nearest the burner, said casing having opposed longitudinal walls thereof provided with inwardly projecting bailes in longitudinally spaced relation between the inlet and outlet ends oi' the casing, each of the rows of bailies providing therebetween a series of stalls which are narrower at their entrances than at their inner ends and adapted to serve as sound trapping chambers, the bames being coveredwlth sound absorbing material.

4. A noise muiiling air delivery tube for an oil burner in a furnace including an elongated muffler casing having an inlet at one'end remote from the burner and an outlet at the other end nearest the burner, said casing having opposed longitudinal walls thereof provided with inwardly projecting bailes in longitudinally spaced relation between the inlet and outlet ends of the casing, each of the rows of bailes providing therebetween a series of stalls which are narrower at their entrances than at their inner ends and adapted to serve as sound trapping chambers. the said longitudinal walls and bailes being covered with sound absorbing material.

5. A noise muming air delivery tube for an oil burner in a furnace including an elongated muffler casing having an inlet at one end remote from the burner and an outlet at the other end nearest the burner, said casing having the opposed side walls thereof provided with inwardly projecting b'ames in longitudinally spaced relation between the inlet and -outlet ends of the casing, each of the rows of bailes providing therebetween a series of stalls which are narrower at their entrances than at their inner ends and adapted to serve as sound trapping chambers, the top, bottom and side walls and baiiles being all covered with sound absorbing material.

' 6. A noise muilling air delivery tube for an-oil v burner in a furnace including an elongated mufiier casing having an inlet at one end remote from the burner and an outlet at the other end nearest the burner, said casing having opposed longitudinal walls thereof provided with inwardly projecting bailles in longitudinally spaced relation between the inlet and outlet ends of the casing, each of the rows of bailles providing therebetween a series of stalls which are narrower at their entrances than at their inner ends and adapted to serve as sound trapping chambers, the balles on one wall of the casing being in staggered relationto the bailes on the. opposite wall.

1. A noise muiiling air delivery tube for an oil burner in a furnace including an elongated mufiier casing having an inlet at one end remote from the burner and an outlet at the other end nearest the burner. said casing having opposed longitudinal walls thereof provided with inwardly projecting bailles in longitudinally spaced relaadapted to serve as sound trapping chambers, the baillesononewallof thecasingbeinginstaggered relation to the baiiies on the opposite wall, the bailles being covered with sound absorbing material.

8. A noise muilllng air delivery tube for an oil burner in a furnace including an elongated muffler casing having an inlet at one end remote from the burner and an outlet at the other end nearest the burner, said casing having opposed longitudinal walls thereof provided with inwardly projecting bailes in longitudinally spaced relation between the inlet and outlet ends of the casing, each of the rows of bailies providing therebetween a series of stalls which are narrower at their entrances than at their inner ends and adapted to serve as sound trapping chambers. the bailies on one wall of the casing being in staggered relation to the bailleson the opposite wall. the said longitudinal walls and bailles being cov-' ered with sound absorbing material.

9. A noise muiliing air delivery tube for an oil burner in a furnace including an elongated muffler casing having an inlet at one end remote from the burner and an outlet at the other end nearest the burner, said casing having opposed longitudinal walls thereof provided with inwardly projecting .bailles in longitudinally spaced relation between the inlet and outlet ends of the casing, each of the rows of baiiles providing therebetween a series of stalls adapted to serve as sound trapping chambers, the outer ends of the bafiies being oi' enlarged cross-section whereby to proportionately restrict the entrance of each of said stalls.

10. A noise muilling air delivery tube for an oil burner in a furnace including an elongated muiiler casing having -an inlet at one end remote from the burner and an outlet at the other end nearest the burner, said casing having opposed longitudinal walls thereof provided with inwardly projecting bailies in longitudinally spaced relation between the inlet and outlet ends o! the casing, each of the rows of bailles providing therebetweena series of stalls adapted to serve as sound trapping chambers. the outer ends of the bailles being of enlarged cross-section whereby to proportionately restrict the entrance of each of said stalls. the bailles being covered with sound absorbing material.

1l. A noise muilling air delivery tube for an oil vburnerin a furnace including an elongated muiiier casing having an inlet at one end remote from the burner and an outlet at the other end nearest the burner, said casing having opposed longitudinal walls thereof provided with inwardly projecting baiiles in longitudinally spaced relation between the inlet and outlet ends of the casing, each of the rows of baflles providing therebetween a series of stalls adapted to serve as sound trapping chambers, the outer ends of the bailles being of enlarged cross-section wherebyv to proportionately restrict the entrance yof each of said stalls, the said longitudinal wallsk therebetween which are narrower at their entrances than at their inner ends, sound absorbing material covering the interior of said chamber and extending over said baille projections, and a covering of sound absorbing material on the inside of said removable cover plate.

13. In a muiliing device, an elongated shell of substantially rectangular cross-section having an inlet opening in one end and an outletropening in the other end thereof, baiiies extending inwardly from the opposed longitudinal walls of said shell toward one another, the inner ends of said baiiles being enlarged, a covering of porous sound absorbent material for the inside walls of said shell and bailies, the sound absorbent material for covering the bailles and the longitudinal walls carrying the same being of flexible sheet form and extending lengthwise of said longitudinal walls between and over the bailles, and means for retaining said sheet material, said means being retained on the banles behind the enlarged inner ends thereof.

14. A noise muilling airA delivery tube for an oil burner in a furnace including an elongated muilier casing having an inlet at one end remote from the burner and an .outlet at the other end nearest the burner, said casing having opposed longitudinal walls thereof provided with inwardly projecting baiiles in longitudinally spaced relation between the inlet and outlet ends of the casing, eachof the rows of baffles providing therebetween a series of stalls which are narrower at their entrances than at their inner ends and adapted to serve as sound trapping chambers.

15. A noise muiiling air delivery tube for an oil burner in a. furnace including an elongated muiiler casing having an inlet at one end remote from the burner and an outlet at the other end nearest the burner, said casing having opposed longitudinal walls thereof provided with inwardly projecting bailies in longitudinally spaced relation between the inlet and outlet ends of the casing, each of the rows of bailles providing therebetween a series of stalls adapted to serve as sound trapping chambers, the outer ends of the bailles being of enlarged cross-section whereby to proportionately restrict the entrance of each of said stalls, the bames on one wall of said casing being in staggered relation to the bailles on the opposite wall.

JOHN H. MCILVAINE. 25 

